1. Field of the Invention
This invention relates to thief-resistant lock devices, as for vehicles, buildings, vaults, deposit boxes, or any application requiring locking devices for security and electrical interlock for safety or warning.
2. Description of the Prior Art
Considerable prior art is known relating to locking systems and alarm systems. Some prior art noted in the course of a search on this subject is as follows:
U.s. pat. No. 3,029,345 Douglas PA1 U.s. pat. No. 3,599,454 Hill et, al. PA1 U.s. pat. No. 3,639,906 Tritsch PA1 U.s. pat. No. 3,660,831 Nicola et, al. PA1 U.s. pat. No. 3,733,862 Killmeyer PA1 U.s. pat. No. 3,889,501 Fort IBM Technical Disclosure Bulletin, Vol. 12, p. 1473
In the Douglas patent, there is a disclosure of a "key-card" in which the light-transmitting characteristics of the card, if correct, will enable activation of a door-opening circuit.
In the Hill et al patent, a special key is provided such as shown in FIGS. 8-14 and 16-19, and which must first be inserted in a reading station, and then be inserted in a lock. Holes or cavities in the key, and associated "micro"-switches, control the lock.
In the Tritsch patent, key-operated pins complete light paths. In FIG. 5, the key has embedded magnets for operating reed switches.
In the Killmeyer reference, there is a combination mechanical and light-actuated lock whereby rotation of a notched key in the tumbler cylinder permits the intersection of a light path by coded apertures which generate a characteristic pattern.
In the Fort patent, lock mechanisms using a pair of light sources and detectors and an apertured key are disclosed. When the key is inserted, light is permitted to pass therethrough whereby an electrical circuit is operated which, in turn, activates a solenoid to permit rotation of the mechanical cyclinder.
In Nicola et al, column 1 speaks of a motor vehicle alarm and column 5 speaks of a false key alarm. The key uses conductive contacts on the surface, to make electrical connections.
In the IBM Technical Disclosure Bulletin, a light-operated lock includes a "micro"-switch 6 for actuating the system when the key is inserted, and alarm means which are actuated if the inserted key is not the correct one.
Three additional references were cited in the original application Ser. No. 681,555. In these, U.S. Pat. No. 3,906,447 discloses the idea of applying the system to an automobile ignition lock. The key itself is simply a card having a particular code arrangement on it and does not have mechanical operating features. Similarly, the opto-electronic security system of the Cestaro U.S. Pat. No. 3,872,435 does not have a key with mechanical features on it for mechanical operations in a lock. The key itself has pulse-train generating means on it.
The Benford U.S. Pat. No. 3,500,326 uses the lugs on the key of FIG. 2 or the combination of lugs and features in the slot of the key of FIG. 15 to operate switches, In contrast, the programmer of FIGS. 12 and 13 can respond to holes in two rows for producing the pulse patterns to operate the apparatus.
I believe there remains a need for locking apparatus of comparatively simple construction and having some features to which the general public is accustomed, while combining new mechanical and optical-electronic locking and alarm features, together with minimal likelihood of susceptibility to decoding or "picking" by unauthorized persons.